Thermochemical Equations, Limiting Reactants and Heating Curves

Heating Curve

A graphical representation showing the temperature of a substance over time as heat is added at a constant rate.

Phase Change

A physical process where a substance transitions from one state of matter (solid, liquid, gas) to another.

Melting Point (m.p.)

The temperature at which a solid substance transitions to a liquid state at a given pressure.

Boiling Point (b.p.)

The temperature at which a liquid substance transitions to a gaseous state at a given pressure.

Molar Heat of Fusion (ΔHfus)

The amount of heat energy required to melt one mole of a solid substance at its melting point under constant pressure.

Molar Heat of Vaporization (ΔHvap)

The amount of heat energy required to vaporize (boil) one mole of a liquid substance at its boiling point under constant pressure.

Specific Heat Capacity (c)

The amount of heat energy required to raise the temperature of one gram of a substance by one degree Celsius (or one Kelvin) without undergoing a phase change.

Enthalpy (H)

The heat content of a substance at constant pressure.

Thermochemical Equation

A balanced chemical equation that includes the enthalpy change (ΔH) for the reaction.

Exothermic Reaction

A chemical reaction that releases heat energy into the surroundings.

Endothermic Reaction

A chemical reaction that absorbs heat energy from the surroundings.

Heat of Reaction (ΔH)

The change in enthalpy for a chemical reaction.

Limiting Reactant

The reactant that is completely consumed first in a chemical reaction, thereby determining the maximum amount of product that can be formed.